[dm-devel] [PATCH v5 7/7] pmem: fix pmem_do_write() avoid writing to 'np' page

[Christoph Hellwig]

On Fri, Jan 28, 2022 at 02:31:50PM -0700, Jane Chu wrote:
> +	if (!bad_pmem) {
>  		write_pmem(pmem_addr, page, page_off, len);
> +	} else {
> +		rc = pmem_clear_poison(pmem, pmem_off, len);
> +		if (rc == BLK_STS_OK)
> +			write_pmem(pmem_addr, page, page_off, len);
> +		else
> +			pr_warn("%s: failed to clear poison\n",
> +				__func__);

This warning probably needs ratelimiting.

Also this flow looks a little odd.  I'd redo the whole function with a
clear bad_mem case:

	if (unlikely(is_bad_pmem(&pmem->bb, sector, len))) {
		blk_status_t rc = pmem_clear_poison(pmem, pmem_off, len);

		if (rc != BLK_STS_OK) {
			pr_warn("%s: failed to clear poison\n", __func__);
			return rc;
		}
	}
	flush_dcache_page(page);
	write_pmem(pmem_addr, page, page_off, len);
	return BLK_STS_OK;